Effects of Endocardial Microwave Energy Ablation

Until recently the treatment of atrial fibrillation (AF) consisted primarily of palliation, mostly in the form of pharmacological intervention. However because of recent advances in nonpharmacologic therapies, the current expectation of patients and referring physicians is that AF will be cured, rather than palliated. In recent years there has been a rapid expansion in the availability and variety of energy sources and devices for ablation. One of these energies, microwave, has been applied clinically only in the last few years, and may be a promising technique that is potentially capable of treating a wide range of ventricular and supraventricular arrhythmias. The purpose of this study was to review microwave energy ablation in surgical treatment of AF with special interest in histology and ultrastructure of lesions produced by this endocardial ablation procedure

Effects of endocardial microwave energy ablation

Until recently the treatment of atrial fibrillation (AF) consisted primarily of palliation, mostly in the form of pharmacological intervention. However because of recent advances in nonpharmacologic therapies, the current expectation of patients and referring physicians is that AF will be cured, rather than palliated. In recent years there has been a rapid expansion in the availability and variety of energy sources and devices for ablation. One of these energies, microwave, has been applied clinically only in the last few years, and may be a promising technique that is potentially capable of treating a wide range of ventricular and supraventricular arrhythmias. The purpose of this study was to review microwave energy ablation in surgical treatment of AF with special interest in histology and ultrastructure of lesions produced by this endocardial ablation procedure

Removal of nitrate and pesticides from groundwater by nano zero-valent iron injection pulses under biostimulation and bioaugmentation scenarios in continuous-flow packed soil columns

This study evaluates the NO3- removal from groundwater through Heterotrophic Denitrification (HDN) (promoted by the addition of acetate and/or an inoculum rich in denitrifiers) and Abiotic Chemical Nitrate Reduction (ACNR) (promoted by pulse injection of zerovalent iron nanoparticles (nZVI)). HDN and ACNR were applied, separately or combined, in packed soil column experiments to complement the scarce research on pulse-injected nZVI in continuous-flow systems mimicking a Well-based Denitrification Barrier. Together with NO3- , the removal of two common pesticides (dieldrin and lindane) was evaluated. Results showed that total NO3- removal (>97%) could be achieved by either bioestimulation with acetate (converting NO3- to N2(g) via HDN) or by injecting nZVI (removing NO3- via ACNR). In the presence of nZVI, NO3- was partially converted to N2(g) and to a lower extent NO2- , with unreacted NO3- being likely adsorbed onto Fe-(oxy)hydroxides. Combination of both HDN and ACNR resulted in even a higher NO3- removal (>99%). Interestingly, nZVI did not seem to pose any toxic effect on denitrifiers. These results showed that both processes can be alterned or combined to take advantage of the benefits of each individual process while overcoming their disadvantages if applied alone. With regard to the target pesticides, the removal was high for dieldrin (>93%) and moderate for lindane (38%), and it was not due to biodegradation but to adsorption onto soil. When nZVI was applied, the removal increased (generally >91%) due to chemical degradation by nZVI and/or adsorption onto formed Fe-(oxy)hydroxides.Peer ReviewedPostprint (author's final draft

Hipertensão arterial: principal fator de risco em doentes com fibrilhação auricular

Introdução: A Fibrilhação Auricular(FA) é uma arritmia que cada vez mais está presente na nossa sociedade. Além da repercussão hemodinâmica, a importância desta arritmia está intimamente relacionada com a presença do acidente vascular cerebral. O objetivo deste estudo foi relacionar a Fibrilhação Auricular com os fatores de risco. Métodos: Este estudo realizou-se consultando todas as histórias clínicas que foram codificadas com FA entre 2009 e 2011. Incluíram-se todos os pacientes que estavam de acordo com os critérios de inclusão: ter FA documentada (por eletrocardiograma ou Holter). De todos os indivíduos selecionados obtivemos 315 pacientes, 47,9% do género masculino e 52,1% do feminino com idades entre 24 a 102 anos. Resultados: Verificámos que a maioria dos indivíduos da amostra tem hipertensão arterial (HTA) 91,7%, seguida de hipercolesterolémia com 57,1%, da Diabetes Mellitus (31.4%), da hipercolesterolémia com 27.3% e da obesidade com 27%. Não verificámos existir uma relação estatística entre a FA e a HTA que poderá ser explicada pela elevada percentagem de indivíduos com HTA presente nesta amostra. Já no que diz respeito à hipercolesterolémia houve uma relação estatisticamente significativa entre a presença deste fator de risco e a presença de FA paroxística com um p= 0.046. Na relação da presença de hipertrigliceridémia nas diferentes tipologias de FA obtivemos um p marginalmente significativo de 0.08. Conclusões: A maioria dos indivíduos deste estudo tem hipertensão arterial, hipercolesterolémia, diabetes, hipertrigliceridémia e obesidade, verificando-se uma relação estatística entre los indivíduos com FA hipercolesterolémia e hipertrigliceridémia.N/

The Atrioventricular Conduction Axis and its Implications for Permanent Pacing

Extensive knowledge of the anatomy of the atrioventricular conduction axis, and its branches, is key to the success of permanent physiological pacing, either by capturing the His bundle, the left bundle branch or the adjacent septal regions. The inter-individual variability of the axis plays an important role in underscoring the technical difficulties known to exist in achieving a stable position of the stimulating leads. In this review, the key anatomical features of the location of the axis relative to the triangle of Koch, the aortic root, the inferior pyramidal space and the inferoseptal recess are summarised. In keeping with the increasing number of implants aimed at targeting the environs of the left bundle branch, an extensive review of the known variability in the pattern of ramification of the left bundle branch from the axis is included. This permits the authors to summarise in a pragmatic fashion the most relevant aspects to be taken into account when seeking to successfully deploy a permanent pacing lead.Sin financiaciónNo data JCR 20211.035 Q1 SJR 2021No data IDR 2021UE

Detailed Anatomical and Electrophysiological Models of Human Atria and Torso for the Simulation of Atrial Activation

Atrial arrhythmias, and specifically atrial fibrillation (AF), induce rapid and irregular activation patterns that appear on the torso surface as abnormal P-waves in electrocardiograms and body surface potential maps (BSPM). In recent years both P-waves and the BSPM have been used to identify the mechanisms underlying AF, such as localizing ectopic foci or high-frequency rotors. However, the relationship between the activation of the different areas of the atria and the characteristics of the BSPM and P-wave signals are still far from being completely understood. In this work we developed a multi-scale framework, which combines a highly-detailed 3D atrial model and a torso model to study the relationship between atrial activation and surface signals in sinus rhythm. Using this multi scale model, it was revealed that the best places for recording P-waves are the frontal upper right and the frontal and rear left quadrants of the torso. Our results also suggest that only nine regions (of the twenty-one structures in which the atrial surface was divided) make a significant contribution to the BSPM and determine the main P-wave characteristics.This work was partially supported by the "VI Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica" from the Ministerio de Economia y Competitividad of Spain and the European Commission (European Regional Development Funds - ERDF - FEDER), Award Number: TIN2012-37546-C03-01 (Recipient: Ana Ferrer); the "Programa Estatal de Investigacion, Desarrollo e Innovacion Orientado a los Retos de la Sociedad" from the Ministerio de Economia y Competitividad and the European Commission (European Regional Development Funds - ERDF - FEDER), Award Number: TIN2014-59932-JIN (Recipient: Rafael Sebastion); and the "Programa Prometeo" from the Generalitat Valenciana, Award Number: 2012/030 (Recipient: Laura Martinez).Ferrer Albero, A.; Sebastián Aguilar, R.; Sánchez Quintana, D.; Rodriguez, JF.; Godoy, EJ.; Martinez, L.; Saiz Rodríguez, FJ. (2015). Detailed Anatomical and Electrophysiological Models of Human Atria and Torso for the Simulation of Atrial Activation. PLoS ONE. 10(11):1-29. https://doi.org/10.1371/journal.pone.0141573S129101

Critical Assessment of the Concepts and Misconceptions of the Cardiac Conduction System over the Last 100 Years: The Personal Quest of Robert H. Anderson

Anatomical concepts regarding the conduction system of the heart have been a matter of debate since pioneering work done at the beginning of the 20th century. Robert H. Anderson was actively involved in this field for half a century. We aimed to investigate how his own concepts evolved over time. We have assessed anatomical concepts relating to the cardiac conduction system appearing since the key contributions made in the initial decade of the 20th century, analyzing them from the perspective of Robert H. Anderson, particularly focusing on the anatomical aspects of structures such as accessory atrioventricular pathways, including the so-called Mahaim-type fibers, connections between the atrioventricular node and the atrial myocardium, and so-called “specialized” internodal atrial tracts. To accomplish this task, we have taken as our starting point the initial concepts published in the first decade of the century, along with those subsequently reported up to 1976, and assessing them in the light of our most recently published works. The concepts put forward by Robert Anderson with regard to atrioventricular nodal bypass tracts, atrioventricular nodal inputs, decrementally conducting accessory pathways, and “tracts” for internodal atrial conduction, have remained consistent along the time frame of half a century

Cavotricuspid isthmus: Anatomy and electrophysiology features: Its evaluation before radiofrequency ablation

The cavotricuspid isthmus (CTI) in the lower pan of the right atrium, between the inferior caval vein and the tricuspid valve, is considered crucial in producing a conduction delay and. hence, favoring the perpetuation of a reentrant circuit. Non-uniform wall thickness, muscle fiber orientation and the marked variability in muscular architecture in the CTI should be taken into consideration from the perspective of anisotropic conduction, thus producing an electrophysiologic isthmus. The purpose of this article is to review the anatomy and electrophysiology of the CTI in human hearts to provide useful information to plan CTI radio frequency ablation for the patients with atrial flutter.Ministerio de Economía y Competitividad (TIN2012-37546-C03-02)0.113 SJR (2014) Q4, 134/164 Bioengineering, 245/329 Biomedical engineeringUE

Cardiac anatomy: What the electrophysiologist needs to know

6.023 JCR (2013) Q1, 12/125 Cardiac & cardiovascular system